The invention relates to a micro reservoir, particularly for integration in a microfluidic flow cell, with a storage space containing a fluid, wherein the storage space is in communication with an outlet duct for the fluid in which a cancelable lock for the fluid is formed.
Micro reservoirs of this type are known from WO2009/071078 A1. The storage space and the outlet duct of this known micro reservoir are formed by two foils arranged on a plate-shaped substrate, wherein the foils are welded or/and glued together so as to define the storage space and the outlet duct. For forming the storage space, the foil facing away from the substrate has a spherically shaped deformation. A welded or/and glued connection of the foils extending linearly transversely of the outlet duct serves as a lock which hermetically tightly seals the storage space. The storage space is formed by a deep drawn expansion of the foil facing the substrate. For opening the storage space, the storage space is pressed together with a deformation of the foil until such a pressure is built up at the lock provided as an intended breaking point, causing a rupture of the intended breaking point.
The substrate constructed as a single piece forms a portion of a processing device for fluids (flow cell) which, in addition to one or several micro reservoirs, may comprise further elements for processing fluids. Among these are elements for supplying liquid or gaseous specimens, mixing elements, pumps, valves, filters for separating components of a fluid, temperature adjusting chambers, detection chambers, lateral flow test strips, transport ducts and waste chambers which, individually or in combination, are used for the analysis and/or synthesis of fluids for medical and pharmaceutical purposes or for analytical processes, such as immune or genetic assays.
Disadvantageously, the fluid pressure required for eliminating the lock causes the fluid to shoot out of the storage space at a high flow speed in the first moment after opening the outlet duct. A partial quantity of the stored fluid leaves the storage space in this manner uncontrolled and unmetered. If the flow cell is intended for reactions which require defined flow speeds of supplied reagents, this partial quantity is lost and, thus, the contents of the micro reservoir cannot be fully utilized.
It is a particular disadvantage that with decreasing total storage quantity the non-usable portion increases, so that especially expensive reagents are lost.